Best casual player ROM hacks

I'm building a Retro Pie for each of my twin sisters for Christmas. While it can emulate PS1 and up to Dreamcast, my sisters were gamers during the NES, SNES, Genesis and N64 era. I have enough space to put all the original game they played from those systems on my 32 GB USB stick so I'm looking for hack suggestion on those systems.

My sisters were really into the Mario games, Disney stuff, some Zelda and some platformers like kid ICarus, Mega Man, Battle Toad, Bubsy, etc. I'm looking for good (but not hardtypes) hacks on those series and hacks from other games that are original and well made. Stay away from shooters, sport games and RPGs.

I have little ROM hacking knowledge outside FF6 so any suggestion is welcome!